DESCRIPTION

Attempts to cancel an iocb previously passed to io_submit. If
the operation is successfully cancelled, the resulting event is
copied into the memory pointed to by result without being placed
into the completion queue.

When one or more requests are asynchronously processed, it might be
useful in some situations to cancel a selected operation, e.g., if it
becomes obvious that the written data is no longer accurate and would
have to be overwritten soon. As an example, assume an application, which
writes data in files in a situation where new incoming data would have
to be written in a file which will be updated by an enqueued request.